Relief Vent for a Hot Fill Fluid Container

ABSTRACT

Caps having porous elements that act as a vent to facilitate cooling of hot fluids stored in containers. Certain embodiments comprise a cap that may be affixed to a container filled with a hot fluid. The cap may include a porous element that allows air to enter the container during the cooling process, but also prevents the introduction of microbes and bacteria into the container. The cap may include a through hole, chamber, or recessed area to receive and secure the porous element. In certain embodiments the porous element may comprise a sintered composite material with thermoplastic particles and either metal particles and/or metal powder. In other embodiments, the porous element may comprise a layered structure. The layers may include a combination of the sintered composite material, a metallic layer, or various porous layers.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent ApplicationSer. No. 61/245,166, entitled “Relief vent for a hot fill beveragecontainer,” filed on Sep. 23, 2009, and to U.S. Provisional PatentApplication Ser. No. 61/204,756, entitled “Relief vent for a hot fillbeverage container,” filed on Jan. 9, 2009, the entire contents of whichare incorporated by reference.

FIELD OF THE INVENTION

Embodiments of the present invention relate to vents and/or barriers forfluid containers, for example beverage containers.

BACKGROUND OF THE INVENTION

When a container is filled with some type of hot fluid and the fluidcools, any gas that is inside the container contracts. This contractionof internal gasses causes a pressure differential between the inside ofthe container and outside of the container (the ambient conditions),which may cause the sidewalls of the container to collapse inward. Thefood processing industry is one example of an industry that mightencounter such problems. For example, in order to maintain productquality and consumer safety, most foodstuffs are packaged in a hot-filloperation in which the foodstuffs are placed in the containers while hot(for example 82° C. or higher), and then a cap is affixed to thecontainer. But such caps seal the contents of the container to ambientconditions. Thus, when the foodstuffs cool, air cannot enter thecontainer to alleviate the pressure differential, and the sidewalls ofthe container may collapse. It should be understood that the foodindustry is but one non-limiting example, and other industries may alsoexperience problems with allowing containers to cool.

One solution is to provide collapsing panels (or vacuum panels) in thesidewalls to alleviate the pressure differential, but such panels havedisadvantages. For example, containers must have thick sidewalls toaccommodate panels, which increases material cost and assembly cost.Additionally, the panels may allow the fluid to leak out of thecontainer and may allow airborne microbes to enter the container.

Another solution is to provide an aperture in one or both of thecontainer or cap, and to provide a hydrophobic membranes to cover theaperture. A hydrophobic membrane is one that allows air but not liquidto pass. Although such membranes may relieve the pressure differential,but they are typically very thin (for example 100 microns) and verydelicate, and thus may become damaged during the manufacturing orcooling process. The membranes increase manufacturing costs becauselamination and/or adhesives are required to secure the membranes.

Thus, there is a need for a structure that can more effectivelyventilate containers filled with hot fluid.

There is a need for a structure to allow ambient air to enter containersfilled with hot fluids to equalize pressures during the cooling process,thus preventing the sidewalls of the container from collapsing.

There is a need for a structure that ventilates containers filled withhot fluids while blocking liquid flow out of the container.

There is a need for a structure that ventilates containers filled withhot fluids without causing the introduction of airborne microbes andbacteria into the container.

There is a need for a sturdy structure that ventilates containers thatwill not become damaged during the manufacturing or cooling process.

There is a need to reduce the material cost and assembly cost of suchcontainers for hot fluids.

SUMMARY OF THE INVENTION

Certain embodiments of the invention comprise a cap that may be affixedto a container that is preferably at least partially filled with a hotfluid. For example, in the food processing industry, containers may befilled with hot foodstuffs or fluids, and it may be desirable to allowthe containers to cool using embodiments of the invention. The cap mayinclude a porous element that facilitates cooling of the hot fluid.Specifically, the porous element may allow air to enter the containerduring the cooling process, thus equalizing pressure on either side ofthe container walls and preventing or minimizing the sidewalls of thecontainer from collapsing. The porous element may also preferablyprevent the introduction of microbes and bacteria into the container.The porous element may be secured to the cap in any number of ways. Forexample, the cap may include a through hole, chamber, or recessed areato receive the porous element. The porous element may be provided in anydesired shape. The porous element is stronger than previously usedmembranes and less susceptible to damage. Additionally, in certainembodiments it is not necessary to use adhesive or lamination to securethe porous element to the cap, thus reducing manufacturing time andexpenses.

According to certain embodiments the porous element may comprise asintered porous plastic. In other embodiments, the porous element maycomprise a sintered composite material with sintered porous plastic andeither metal particles and/or metal powder. In still other embodiments,the porous element may comprise a layered structure with at least oneporous plastic layer and at least one metallic layer.

Regardless of the composition of the porous element, in certainembodiments the porous element contains pores that allow for the passageof air into and out of the container during the cooling process, butthat also prevent the passage of microbes and bacteria. Upon sufficientcooling, heat may be applied to the porous element if desired, thussealing the porous element and the cap.

BRIEF DESCRIPTION OF THE FIGURES

FIGS. 1A-C are perspective cross-sectional views of one embodiment of acap having a porous element.

FIGS. 2A-C are perspective cross-sectional views of another cap having aporous element. FIG. 2D is a detailed view of FIG. 2C. FIG. 2E is aperspective cross-sectional view of an alternative embodiment for thecap and porous element shown in FIGS. 2A-2D.

FIGS. 3A and 3B are perspective cross-sectional views of another caphaving a porous element.

FIGS. 4A-C are perspective cross-sectional views of yet anotherembodiment of a cap having a porous element.

FIG. 5 is a perspective cross-sectional view of one embodiment ofsealing a cap having a porous element.

FIG. 6A is a cross-sectional view of another embodiment of a cap havinga porous element, wherein the porous element is in the shape of a plug.FIG. 6B is a perspective view of the porous element shown in FIG. 6A.

FIG. 7A is a perspective view of an insert containing a porous elementfor use in caps. FIGS. 7B and 7C are cross-sectional perspective viewsof the insert (shown in FIG. 7A) affixed to a cap.

FIG. 8 is a microscopic view of one embodiment of a sintered porousplastic.

FIG. 9A is a microscopic view of one embodiment of a sintered compositematerial. FIG. 9B is a microscopic view showing another embodiment of asintered composite material.

FIGS. 10A and 10B are both microscopic views of certain embodiments of afirst layered structure, comprising a layer of sintered compositematerial and a layer of sintered porous plastic.

FIG. 11 shows an embodiment of a second layered structure, comprising aporous layer and a metallic layer.

FIG. 12 shows an embodiment of a third layered structure, comprising atleast two porous layers and a metallic layer there between.

FIG. 13 shows certain embodiments for manufacturing the layeredstructures described herein.

FIGS. 14 and 15 show an exemplary cap having a porous element affixed toa container.

DETAILED DESCRIPTION

According to certain embodiments of the invention, caps are providedwith porous elements that function as a vent to allow air to pass intoor out of a container during the cooling process, and also act as abacterial barrier to prevent microbial and bacterial contamination. FIG.14 shows one embodiment of a container 160 fitted with cap 80. Container160 has a neck, where the neck has an external thread. The container 160may preferably be filled with a hot fluid 162. “Fluid” may include anyliquid, gas, and may also include some solid substances (particularlyincluding foodstuffs). All the caps described herein may be secured tothe container 160 in the same manner as shown in FIG. 14. Thus, unlessotherwise indicated, the caps may include sidewalls 12 having threads 18to mate with corresponding threads on the neck of the container 160,forming a screw top seal. The caps may optionally include a brim 16 thatmay fit inside the neck of the container 160 to provide additionalprotection against the fluid inside the container from leaking.

The embodiment of cap 10 shown in FIG. 1 includes a chamber 22 definedby chamber sidewalls 20. The chamber 22 may be any desired height orwidth, and may have any desired shape. In its initial state, the chamber22 has two openings—a bottom end 26 and a through hole 28. The throughhole 28 is defined by a protrusion 24 on the outer surface 14 of the cap10. The bottom end 26 extends downward into the cap 10, and isdimensioned to receive a porous element 30. As shown in FIG. 1A, theporous element 30 may be inserted into the chamber 22 through the bottomend 26. If desired, a porous element 30 may be selected with dimensionsthat closely conform to the side walls of the chamber 22 such that afriction fit is formed between the porous element 30 and the chamber 22.As shown in FIG. 1B, after the porous element 30 is inserted, a tool 32may be used to crimp the chamber sidewalls 20 to secure the porouselement 30 within the chamber 22. If desired, the bottom end 26 may bechamfered to facilitate crimping of the chamber sidewalls 20. As shownin FIG. 1C, the chamber sidewalls 20 need not be fully closed or crimpedtogether. Rather, there may still be an opening 34 after the crimpingstep to facilitate the cooling process and the flow of air into thecontainer.

In other embodiments, the cap 40 in FIG. 2A-E includes a recessed area42 that is dimensioned to receive a porous element 46 that isdisc-shaped. The particular size and shape of the recessed area 42 isnot essential, provided that it can receive the porous element 46. Incertain embodiments the outer edges of the recessed area 42 are definedby a lip 44. As shown in FIG. 2B, a tool 32 may be used to crimp downthe lip 44 over the porous element 46, securely holding the porouselement 46 in place. FIGS. 2C and D show the completed cap 40 with acrimped lip 44. A slightly modified version of cap 40 is shown in FIG.2E. Rather than having a lip 44, certain embodiments may have aplurality of tabs 48 that extend over the porous element 46. Thus, itshould be understood that there are multiple ways to secure the porouselement 46 to the cap 40—some embodiments may include lip 44, others aplurality of tabs 48, and still others may have other members to securethe porous element 46 to the cap 40.

According to certain embodiments, such as cap 50 shown in FIG. 3, aprotrusion 24 may define a through hole having a wide portion 52 and anarrow portion 54. The porous element 56 may be press fitted into thewide portion 52 to form a friction fit to secure the porous element 56into the wide portion 52.

In yet other embodiments, such as those shown in FIGS. 4A-B, cap 60 isprovided with a laminated structure 62 that comprises at least oneporous element 64 and at least one substrate 66. Non-limiting examplesfor the substrate 66 may include polyethylene (PE) or polypropylene(PP). There may be an aperture 68 in the substrate 66 that exposes theporous element 64, thus providing a passage for air to flow into thethrough hole 28 and through the porous element 64. The porous element 64may be laminated, welded, adhered to, or otherwise attached to thesubstrate 66. In some embodiments the laminated structure 62 may beinserted into the cap 60 such that the porous element 64 contacts theinner surface 61 of the cap 60. But in other embodiments the laminatedstructure 62 may be flipped such that the substrate 66 contacts theinner surface 61. In either configuration, the porous element 64 isgenerally positioned over the through hole 28. A slightly modifiedversion of cap 60 is shown in FIG. 4C. Rather than having a laminatedstructure 62 with a substrate 66, certain embodiments may have anextended porous element 67 that is dimensioned to cover substantiallyall of the inner surface 61 of the cap 60.

In certain other embodiments there may be provided a plug-shaped porouselement 82, such as shown in FIGS. 6A and 6B. The head 84 may sit abovethe outer surface 14 of the cap 80, and the body 86 may be inserted intothe through hole 28. If desired, the head 84 may be color-matched to theouter surface 14 of the cap 80, have a logo or design, or otherwise thehead 84 may be aesthetically pleasing. The plug-shaped porous element 82may be formed by molding, or by machining other porous elements (such asthe cylindrically-shaped porous elements 30, 56). As described morethoroughly herein, in certain embodiments the plug-shaped porous element82 may comprise a layered structure. In one specific and non-limitingexample, a plug-shaped porous element 82 was formed from polyethylene,and the element 82 had a height of 5 mm. The pore size in this specificexample was approximately 14 μm. The plug-shaped porous element 82 wasfound to have a bacterial filtration efficiency of over 99.9% based onthe ASTM 1200 test, and an air flow of 9 liters per minute. The samebacterial filtration efficiency and air flow rate was achieved inanother non-limiting example, where the porous element 82 was made ofultra high molecular weight polyethylene (UHMWPE) and the pore size wasapproximately 7-10 μm.

Although the embodiments have been described as having separate caps andporous elements that are subsequently assembled together, it should beunderstood that in certain embodiments the porous elements may bemanufactured into the caps by insertion molding. For example, in FIG. 1,porous element 30 may be insertion molded into the chamber 22. In FIG.2, the porous element 46 may be insertion molded into the recessed area42 and in FIG. 3, the porous element 56 may be injection molded into thewide portion 52.

Once the porous element is secured within the cap, the cap may beaffixed to the container, as shown in FIG. 14. Although FIG. 14 shows aplug-shaped porous element 82, it should be understood that all the capsdescribed herein may be secured to the container 160 in the same manner.As the hot fluid 162 within the container 160 cools, any gas inside thecontainer 160 may contract and result in lower pressure inside thecontainer 160 than outside. Air moves from areas of high pressure(outside the container 160) to areas of low pressure (inside thecontainer 160), and thus, air may flow into through hole 28, passthrough porous element 82, and into the container 160. The flow of airinto the container 160 equalizes pressure between the exterior andinterior of the container 160 and prevents the sidewalls of thecontainer 160 from collapsing. Additionally, as described more fullybelow, the porous element 82 preferably has sufficiently small pores toprevent the passage of any microbial mater into the container 160. Insome embodiments, the porous elements described herein have a bacterialfiltration efficiency of over 99.9% based on the ASTM 1200 test.

When sufficient time for cooling has passed, the cap may be sealed inorder to minimize or prohibit any further flow of air into or out of thecontainer. FIG. 5 shows one method for sealing cap 10, where a heatingtool 70 is used to heat the protrusion 24, which causes the material tomelt. The protrusion 24 will then re-harden to seal the cap 10. This canbe accomplished using a variety of techniques, such as spin weldingtechniques with a forming die, sonic welding, heat sealing, or anysimilar procedure. In other embodiments, the porous element itself maybe sealed by heating the porous element until it becomes non-porous(also referred to as sealed). For example, in FIG. 15, the plug 82 maybe heated (represented by the spirals 164) such that the plug 82 becomesnon-porous and seals the cap 80. Yet another technique is to inject asealant into the through hole 28 and allow the sealant to cure, thussealing the through hole 28 (not shown).

Yet another embodiment of a cap 88 having a porous element 96 is shownin FIGS. 7A-C. FIG. 7A shows insert 90, which is generally cylindricaland includes a plurality of side holes 92. A porous element 96 iscontained within the insert 90, and is exposed by the side holes 92. Ifdesired, the outer surface 94 of the insert 90 may be non-porous. FIG.7B shows the insert 90 and cap 88 in an initial position, where the sideholes 92 are above the outer surface 14 of the cap 88 and are exposed toambient conditions. The cap 88 may be affixed to a container (such ascontainer 160 shown in FIG. 14) and any contents within the containermay be allowed to cool. In this initial position, ambient air may enterthe side holes 92, go through the porous element 96, and into thecontainer. When sufficient time for cooling has passed, the insert 90may be pressed into the cap 88 such that the side holes 92 are no longerexposed to ambient conditions. Thus, in FIG. 7C, the side holes 92 arebeneath the inner surface 61 of the cap 88. In embodiments wherein theouter surface 94 of the insert 90 is non-porous, the cap 88 is sealed inthis second position. If desired, a wax or sealant may be applied to theouter surfaces 14, 94 in order to further seal the cap 88.

According to certain embodiments, the porous elements described hereinare sintered and may be made from a variety of materials. Certainmaterials for the porous elements are described in FIGS. 8-12. But othersuitable materials include polytetrafluoroethylene (PTFE), polyethylene,polypropylene, and polyesters. Polyethylene includes high densitypolyethylene (HDPE) and ultra high molecular weight polyethylene(UHMWPE). The average pore sizes of porous elements for use in certainembodiments of the invention may be from 0.1 micron to 50 microns. Ifdesired, a porous element may comprise a laminated structure, where thelaminated structure comprises a polymer and a substrate and/or amembrane. Examples of substrates include other porous polymers,non-woven or woven fibers, a non-woven or woven sheet or plastic tubes.Examples of membranes include polyvinylidene fluoride (PVDF) membranes,nylon membranes, polyethylene membranes, ultrahigh molecular weightpolyethylene micro fiber membranes, polypropylene membranes, polysulfoneor polyethersulfone membranes. These membranes generally have pore sizesfrom 0.1 microns to 5 microns and are available from MilliporeCorporation (based in Billerica, Mass.), Pall Corporation (based in PortWashington, N.Y.), General Electric Company (based in Fairfield, Conn.),and Koninklijke DSM N.V. (based in the Netherlands). Other materialsthat may be used for the porous elements (shown in FIGS. 8-10) will nowbe described.

FIGS. 8-10 are microscopic views of materials that may be used to makethe porous elements described herein. The materials have already beensintered and are in a solid form. Before being sintered, however, theindividual particles are loose and have no shape. The particles may beplaced into a mold, and the mold (and/or the particles) may be heated tosinter the material into a solid. Despite being sintered, the materialsstill have pores 108 to allow air to pass through the materials, whileat the same time blocking bacteria and microbes. Upon being sintered,the materials may be shaped into any desired porous element and insertedinto a cap.

FIG. 8 shows an embodiment of a sintered porous plastic 122 comprised ofa plurality of thermoplastic particles 102. The thermoplastic particles102 may include any suitable thermoplastic material, including but notlimited to polyolefins, polyethylene (PE), low density polyethylene(LDPE), high density polyethylene (HDPE), ultra high molecular weightpolyethylene (UHMWPE), polypropylene (PP), ethylene vinyl acetate (EVA)or their copolymers. The pores 108 in the sintered porous plastic 122allow air to pass through, but at the same time the pores 108 blockbacteria and microbes. In specific and non-limiting examples, acollection of four porous elements comprising the sintered porousplastic 122 were formed using polyethylene particles. The porouselements varied in thickness between 1.6 and 3.2 mm. The pore sizes inthe porous elements ranged between 10 and 12 μm. Each of the porouselements were found to have a bacterial filtration efficiency of over99.9% based on the ASTM 1200 test, and an air flow of 28 liters perminute.

FIGS. 9A and 9B illustrate embodiments of a sintered composite material100. The sintered composite material 100 shown in FIG. 9A comprisesthermoplastic particles 102 and metal particles 104, whereas theembodiment shown in FIG. 9B comprises thermoplastic particles 102 andmetal powder 106. The thermoplastic particles 102 may be as described inFIG. 8. The metal particles 104 and/or the metal powder 106 may be madeof any suitable metal, including but not limited to steel, stainlesssteel, aluminum, copper, tin, iron, or their alloys. The metal particles104 shown in FIG. 9A are generally larger than the metal powder 106shown in FIG. 9B. As a result, the larger metal particles 104 result ina larger pore 108 size than shown in FIG. 9B. It should be understoodthat the figures are merely exemplary, and that the relative sizes ofthe pores 108 or the particles 104 and powder 106 are not necessarily toscale. The pores 108 in the sintered composite material 100 allow air topass through, but at the same time the pores 108 block bacteria andmicrobes.

FIGS. 10A and 10B illustrate certain embodiments of a first layeredstructure 120, comprising at least a layer of sintered compositematerial 100 and a layer of sintered porous plastic 122. Although theboundary lines between the respective layers 100, 122 in FIGS. 8A and 8Bare both well-defined, it should be understood that in application, theboundary line may be less defined. The sintered composite material 100may be as described in either FIG. 9A or 9B, and the sintered porousplastic 122 may be as described in FIG. 8. The first layered structure120 may be formed in one of several ways. For example, the layers may beformed separately and then joined together, as one of skill in the artwould understand. Another possible method is molding. A first portion ofa mold cavity may be filled with a mixture containing both thermoplasticparticles 102 and either metal particles 104 or metal powder 106 (toform layer 100). A second portion of the cavity may be filled withthermoplastic particles 102 (to form layer 122). The thermoplasticparticles 102 within the respective layers may have the same size orshape, and may be composed of the same material, or they may bedifferent.

FIG. 11 illustrates an embodiment of a second layered structure 130 thatincludes at least a metallic layer 132 and a porous layer 144. Themetallic layer 132 may contain some type of perforation 134. Forexample, the metallic layer 132 may comprise metal mesh, metal foil withholes, or a metal screen, and may be made of steel, stainless steel,aluminum, copper, zinc, tin, iron, or their alloys. The porous layer 144may comprise sintered porous plastic 122, sintered composite material100, polymer membranes, polyethylene (PE), polypropylene (PP),polytetrafluoroethylene (PTFE), expanded PTFE (e-PTFE), polyvinylidenefluoride (PVDF), polyethersulfone (PES) or nylon. Although the porouslayer 144 may vary depending upon application, it may be desirable forthe porous layer 144 to have relatively small pores 108 to act as abacterial barrier.

In its initial state, the second layered structure 130 is porous toallow the passage of air. The metallic layer 132 does not obstruct thepassage of air due to the perforations 134 in the metallic layer 132.Additionally, the pores 108 in the porous layer 144 are sized to allowair to pass, but also act as a bacterial barrier. In some embodiments,the porous layer 144 has a bacterial filtration efficiency of over 99.9%based on the ASTM 1200 test. Upon sufficient heating, the porous layer144 may become non-porous. Specifically, the pores 108 in the porouslayer 144 may melt, thus sealing the second layered structure 130 andpreventing air from entering or exiting the container.

FIG. 12 illustrates an embodiment of a third layered structure 140,which may contain a first porous layer 142, a metallic layer 132, and asecond porous layer 144. The metallic layer 132 and the second porouslayer 144 may be similar to those described above and depicted in FIG.11. The first porous layer 142 may be initially porous. Non-limitingexamples for the first porous layer 142 include sintered porous plastic122, sintered composite material 100, polymer screen, polymer non-wovenor woven materials, or a polymer open cell foam. Thus, in the initialstate of the third layered structure 140, the first and second porouslayers 142, 144 both contain pores 108 and the metallic layer 132contains perforations 134 to allow for the passage of air into or out ofthe container. Additionally (and as shown in FIG. 12), the second porouslayer 144 has smaller pores 108 than the first porous layer 142. Thus,the second porous layer 144 may act as a barrier to prevent microbesand/or bacteria from passing through the third layered structure 140.

Upon sufficient heating the third layered structure 140 may becomesealed. Specifically, it may be desirable to provide a first porouslayer 142 that melts more readily than the second porous layer 144, sothat the first porous layer 142 may become non-porous. Thus, the firstporous layer 142 may have a higher melt index, lower meltingtemperature, and/or a lower viscosity than the second porous layer 144.Materials with a high melt flow index and low viscosity tend to minimizeor eliminate any pores 108 that may be formed therein. And if the firstporous layer 142 has a lower melting temperature than the second porouslayer 144, then it will melt first. Thus, upon sufficient heating thefirst porous layer 142 may be non-porous to seal the container.

According to certain embodiments, the first porous layer 142 maycomprise a colored polymer screen and the metallic layer 132 maycomprise a metal screen. Upon heating, the colored polymer screen andthe metal screen melt together to seal the third layered structure 140.In other embodiments, the first porous layer 142 may comprise a coloredpolymer open-celled foam, the metallic layer 132 may comprise a metalscreen, and the second porous layer 144 may comprise a bacterial barriermembrane, which may then be non-contact heated with an air jet to meltthe colored polymer open-celled foam and thus seal the third layeredstructure 140.

Certain methods of making layered structures are illustrated in FIG. 13.The particular method in FIG. 13 may be useful if the layered structurescomprise materials that may be rolled onto drums (such as screens,membranes, or woven materials). Thus, drum 150 may supply the firstporous layer 142, drum 152 may supply the metallic layer 132, and drum154 may supply the second porous layer 144. The respective layers areextended off the drums. If desired, an adhesive may be applied betweenlayers so that they adhere together. A tool 156 may be used to punch thelayers into the desired shape. The finished layered structure may thenbe inserted into a cap to serve as a porous element (as in FIGS. 1-7).Although the method in FIG. 13 has three drums (150, 152, 154) and thuspertains to the third layered structure 140, one of ordinary skill inthe art would understand how to modify the method to make the secondlayered structure 130, for example, by not providing the drum 150 thatsupplies the first porous layer 142. Other modifications to produceother layered structures are also known to one of skill in the art.

In embodiments comprising metal (such as the sintered composite material100 or any of the layered structures), induction heating may be used tosinter and/or seal the material. Induction heating is generally known toone of skill in the art as a process of heating an electricallyconducting object by electromagnetic induction, where a high-frequencyalternating current (AC) is generated within the metal and resistanceleads to heating of the metal. For example, when the sintered compositematerial 100 is induction heated, the temperature of the metal particles104 may increase, because metal is a good conductor. The radiant heatfrom the metal particles 104 melts the surrounding thermoplasticparticles 102. Upon sufficient heating the material may becomenon-porous, thus sealing the cap.

In certain embodiments, the materials described herein—such as sinteredporous plastic 122, sintered composite material 100, and/or the layeredstructures—may have specific shapes or sizes to facilitate their asporous elements. For example, they may be cylindrically shaped (likeporous elements 30 or 56), disc-shaped (like porous elements 46, 64 67),or shaped like the plug 82 shown in FIGS. 6A-6B. In certain embodimentsthe plug 82 may be formed of a layered structure, such as the layeredstructures 120, 130, or 140. At least a portion of the head 84 maycomprise a material that is initially porous but that becomes non-porousand sealed upon sufficient heating, and at least a portion of the body86 may comprise a material that acts as a bacterial barrier. Forexample, the head 84 may comprise the porous layer 142 or the metalliclayer 132 and the body 86 may comprise porous layer 144. Such a layeredstructure may be formed by molding.

Caps having porous elements as described herein may be prone totampering. For example, if the porous element is exposed or visible thenpeople may tend to pick at the porous element. Such tampering may causeinjury to the person and may sacrifice the seal of the cap. Thus, it maybe desirable to provide tamper-resistant properties to caps and/orporous elements. In one embodiment, the head 84 of the plug 82 describedabove may melt to and become fused with the rest of the cap 80, whichreduces tampering. In embodiments having a metallic layer 132, thestrength of the metallic layer 132 may make it exceedingly difficult totamper with the porous element and/or cap. Thus, the sealing andstrength of certain embodiments provide tamper-resistant properties.

If desired, any of the layered structures described herein may containone or more additional layers. In embodiments where the porous layer 142is not itself non-porous or sealed, a separate hydrophobic layer may beprovided, including but not limited to wax, an adhesive sealant, orpolyethylene. Similarly, although in some embodiments the first porouslayer 142 and/or the metallic layer 132 may be tamper-resistant, inother embodiments a separate tamper-resistant layer may be provided.Finally, the layered structures may be provided with oxygen scavengerproperties. When air enters the container during the cooling process, acertain amount of air (and oxygen) may remain in the container evenafter cooling and sealing of the porous element. The remaining oxygenmay cause unpleasant properties, such as distaste of the contents in thecontainer. Thus, one or all of the layers in the various layeredstructures (120, 130, 140) may contain iron powder, which reacts withand eliminates oxygen in the container.

The foregoing is provided for purposes of illustration and disclosure ofembodiments of the invention. It will be appreciated that those skilledin the art, upon attaining an understanding of the foregoing may readilyproduce alterations to, variations of, and equivalents to suchembodiments. Accordingly, it should be understood that the presentdisclosure has been presented for purposes of example rather thanlimitation, and does not preclude inclusion of such modifications,variations and/or additions to the present subject matter as would bereadily apparent to one of ordinary skill in the art.

1. A cap for a container, the cap comprising: a. a top surface having anouter edge, a first side, and a second side opposite the first side,wherein the second side faces towards the container; b. at least onesidewall extending from the outer edge of the top surface and towardsthe second side, wherein the at least one sidewall is at least partiallythreaded to engage with a neck of the container; c. at least one throughhole defined by the top surface and passing between the first side andthe second side; and c. a porous element adjacent to the top surface andgenerally aligned with the through hole, wherein the porous elementcomprises a plurality of pores that allow air to enter the container butprohibit bacteria from entering the container.
 2. The cap as in claim 1,further comprising at least one chamber wall extending from the secondside of the top surface of the cap, wherein the chamber wall defines achamber that receives the porous element.
 3. The cap as in claim 1,further comprising at least one chamber wall extending from the firstside of the top surface of the cap, wherein the chamber wall defines achamber that receives the porous element.
 4. The cap as in claim 1,wherein the second side of the top surface of the cap defines a recessedarea, and the porous element is secured within the recessed area.
 5. Thecap as in claim 4, further comprising a lip extending around at least aportion of the recessed area, wherein the lip secures the porous elementwithin the recessed area.
 6. The cap as in claim 4, wherein the porouselement is disc-shaped.
 7. The cap as in claim 1, further comprising aprotrusion extending from the first side of the top surface of the cap,and wherein the through hole is defined by the protrusion.
 8. The cap asin claim 1, further comprising a layered structure comprising the porouselement and at least one substrate, wherein the layered structurecontacts the second side of the top surface of the cap.
 9. The cap as inclaim 1, wherein the porous element covers substantially all of thesecond side of the top surface of the cap.
 10. The cap as in claim 1,wherein the porous element has a head and a body, and wherein the bodyis inserted into the through hole and the head contacts the first sideof the top surface of the cap.
 11. A device for facilitating the coolingof fluids within a container, the device comprising: a. a cap, the capcomprising: a top surface having an outer edge and at least one sidewallextending from the outer edge of the top surface, wherein the at leastone sidewall is at least partially threaded to engage with a neck of thecontainer; at least one through hole defined by the top surface; and b.a porous element adjacent to the top surface and generally aligned withthe through hole, the porous element comprising: a metallic layercomprising a plurality of perforations; a porous layer comprising aplurality of pores that allow air to enter the container but prohibitbacteria from entering the container.
 12. The device as in claim 11,wherein the porous layer comprises at least one of sintered porousplastic, sintered composite material, porous polyethylene, porouspolypropylene, polytetrafluoroethylene, expandedpolytetrafluoroethylene, porous polyvinylidene fluoride, porouspolyethersulfone, or porous nylon.
 13. The device as in claim 11,wherein the metallic layer comprises at least one of metal mesh, metalfoil with holes, or a metal screen.
 14. The device as in claim 11,wherein the metallic layer comprises at least one of steel, stainlesssteel, aluminum, copper, zinc, tin, iron, or their alloys.
 15. Thedevice as in claim 11, wherein the porous layer is a second porouslayer, and wherein the device further comprises a first porous layer.16. The device as in claim 15, wherein the first porous layer comprisesa material having at least one of a higher melt index, lower meltingtemperature, and/or a lower viscosity than the material comprising thesecond porous layer.
 17. The device as in claim 15, wherein the firstporous layer becomes non-porous after melting.
 18. The device as inclaim 15, wherein the first porous layer is adjacent to the top surfaceof the cap, and the metallic layer is positioned between the firstporous layer and the second porous layer.
 19. The device as in claim 15,wherein the first porous layer comprises at least one of polymer screen,polymer non-woven material, polymer woven material, or a polymer opencell foam.
 20. The device as in claim 11, wherein the porous elementcomprises a head and a body, and wherein at least a portion of the headcomprises the metallic layer and at least a portion of the bodycomprises the porous layer.
 21. A device for facilitating the cooling offluids within a container, the device comprising: a. a cap, the capcomprising: an outer surface having an outer edge and at least onesidewall extending from the outer edge of the outer surface, wherein theat least one sidewall is at least partially threaded to engage with aneck of the container; at least one aperture defined by the outersurface; and b. an insert secured within the aperture of the cap, theinsert comprising: an outer surface having an outer edge and at leastone sidewall extending from the outer edge of the outer surface, whereinthe at least one sidewall defines at least one through hole; a porouselement secured within the insert and generally aligned with the throughhole, the porous element comprising a plurality of pores that allow airto enter the container but prohibit bacteria from entering thecontainer, wherein in a first position the through hole of the insert isabove the outer surface of the cap, and in a second position the throughhole of the insert is below the outer surface of the cap.
 22. A methodof cooling fluid within a container, the method comprising: a. providinga container at least partially filled with fluid; b. providing a devicecomprising: i. a cap, the cap comprising a top surface having an outeredge and at least one sidewall extending from the outer edge of the topsurface, wherein at least a portion of the sidewall comprises structureto engage with a neck of the container, and wherein the top surfacedefines at least one through hole; ii. a porous element adjacent to thetop surface and generally aligned with the through hole, wherein theporous element comprises a plurality of pores that allow air to enterthe container but prohibit bacteria from entering the container; c.engaging the device to the neck of the container; d. allowing the fluidto cool, wherein during cooling air enters or exits the containerthrough the porous element; and e. applying heat to at least one of thethrough hole or the porous element to thereby seal the device.